This invention relates to a capsule for making beverages. In particular reference is made to those capsules comprising an outer body and a lid which closes the top of the outer body and in which a powdered food substance (for example coffee powder) is positioned, which can be extracted by passing water (which may be pressurized) through it to make a beverage, for example coffee. More specifically reference is made to those capsules in which the outer body comprises a lower wall and a side wall which form a chamber in which a rigid or semi-rigid filtering body is positioned.
In more detail, reference is made to those capsules suitable for use in beverage making systems in which the capsule is pierced at the lid, to allow the injection of water (which may be pressurized) into the capsule itself, and at the lower wall, to allow dispensing outside the capsule of the beverage produced by the interaction of the water with the powdered food substance.
In such capsules the filtering body is substantially a flat filtering body, normally disk-shaped, positioned close to the lower wall of the capsule outer body and separates the powdered food substance from the lower wall in such a way that powder does not come out of the capsule after a piercing element has penetrated through the lower wall. In fact, the filtering body on one hand allows the beverage to pass through it in such a way that said beverage can come out of the capsule through the lower wall (through a hole made by the piercing element or through a channel present in the latter), and on the other hand allows the powdered food substance to be retained in the capsule.
However, this prior art technology may have several disadvantages under certain circumstances.
In particular, with some types and particle sizes of the powdered food substance, and in the case of dispensing relatively high quantities of beverage (such as American coffee), the prior art capsules may not allow optimum extraction of the powdered food substance. In fact, for example, the beverage made by the interaction between the water and the powder located close to the lid, in order to be able to come out of the capsule must reach the filtering body and therefore must pass through all of the powder below which may obstruct its path. In fact, once moistened with the water, the powdered food substance tends to become compacted, obstructing the flow of the liquids which encounter increased resistance to permeation through the powder.
In fact, the water injected into the capsule tends to cause compacting of the powdered food substance at the filtering body, therefore increasing the resistance of the powdered food substance to the passage of the water through it and resulting in difficulties draining the beverage through it.
Moreover, during the injection of water into the capsule, areas are created in the powder which are compacted to different degrees. Therefore, prior art capsules have the disadvantage that the powdered food substance can only be permeated unevenly, that is to say, to drastically different degrees depending on the position of the powdered food substance in the capsule. Moreover, in prior art capsules, since the water tends to flow in the zones of the powder which are less resistant to permeation, preferential channels for the passage of the water are easily created, the result being that the powdered food substance is not all permeated homogeneously.
A first solution which overcomes those disadvantages is described in Italian patent application No. VR2012A000133 and in the corresponding U.S. patent application Ser. No. 13/549,904 in the name of this Applicant, whose content had still not been disclosed at the time of filing this patent application.
In that case, the disk-shaped filter was replaced with a rigid or semi-rigid filter having the shape of a basket with openings at its side wall, which is distanced from the inner part of the side wall of the outer body. Thanks to that solution it was practically possible to avoid the various clogging problems which may arise with prior art capsules.
However, even that solution did not allow all possible disadvantages to be overcome. In particular, when the powdered substance is not adequately ground and contains an excessive quantity of powder which is below a predetermined particle size, it is possible that powder will leak out with the beverage, with consequent deterioration of the quality of the beverage itself (even if, as is known, the leakage of an extremely small quantity of powder is substantially normal in the preparation of beverages of this type, and in particular of coffee).
Finally, there are also prior art capsules in which in place of a rigid or semi-rigid flat filter there is a conical or frusto-conical filter consisting of a layer of flexible material. However, even these capsules have significant disadvantages. In particular, in the case of dispensing relatively large quantities of beverage, such as American coffee, when the powder gets wet it tends to become compacted on the bottom of the filter, substantially clogging it. At that point the extraction water can no longer penetrate the powder and tends to bypass it, coming out of the filter laterally, above the powder, therefore without any extraction effect. Therefore, the resulting beverage is of poor quality.